KEY POINTS:
Just over half of Africa's 52 countries speak French, but the number is dropping. Rwanda has just defected, announcing that henceforward only English will be taught in the schools. It would not be overstating the case to say that this caused alarm and despondency in France.
You couldn't help feeling, either, that Rwanda's Trade and Industry Minister, Vincent Karega, was deliberately rubbing salt in the wound when he explained why French was being scrapped.
"French is spoken only in France, some parts of West Africa, and parts of Canada and Switzerland," he said. (In parts of Belgium, too, actually, not to mention Haiti, but you get the point.)
"English has emerged as a backbone for growth and development not only in the region but around the globe."
No country cares more passionately for its language than France, and it has waged a long and expensive campaign to guarantee the survival of a French-speaking zone in Central and West Africa. It even provided the bulk of the foreign aid for the former Belgian colonies that spoke French: Congo, Rwanda, and Burundi.
But the present Government of Rwanda has special reasons not to be fond of France. Getting very close to the regimes in African countries that have French as an official language, even sending troops to protect them from their domestic enemies, has always been part of Paris' strategy for preserving the status of French as a world language.
In Rwanda's case, that put France in bed with the extremist Hutu-dominated regime that began murdering the minority Tutsis in industrial quantities in 1994.
France did not abandon it. The French President at the time, Francois Mitterrand, is alleged to have remarked that "in such countries, genocide is not too important".
A main reason that France overlooked its Rwandan ally's ghastly behaviour was that the Tutsi-led opposition in exile mostly spoke English, because its members had found refuge in anglophone Uganda.
An estimated 800,000 Tutsis and moderate Hutus were slaughtered in 1994, but the Uganda-based Rwanda Patriotic Front ended the genocide by invading and overthrowing the regime. Even a direct French military intervention (thinly disguised as a humanitarian operation) could not save the Hutu "genocidaires", as they are known.
So it was not to be expected that the new, mainly English-speaking Government in Rwanda would have warm feelings towards France.
The Government defends the scrapping of French teaching in schools as a purely business decision, driven by Rwanda's membership in the largely English-speaking East African Community (Kenya, Uganda, Tanzania, Rwanda and Burundi).
But there is no question that resentment of France also plays a role. This is a country that has already expelled the French ambassador and closed the French cultural centre, international school and radio station.
But can an African country just switch from one European language to another?
It can if, like Rwanda, it uses only one language domestically. Almost all Rwandans, whether Hutu or Tutsi, speak Kinyarwanda, so they have no need for a lingua franca to communicate among themselves. Only those going into higher education or working with foreigners need any other language at all - which is why only 8 per cent of Rwandans speak fluent French after all this time.
This is far from typical of African countries, most of which have many different ethnic groups, each with its own language. Such countries use the language of the former colonial power as a neutral "national" language, and have such a large investment in teaching it by now that switching is out of the question.
The Congo will always use French; Nigeria will always use English; Mozambique will always use Portuguese.
So francophones can relax: their language is not about to vanish from the African continent. On the other hand, French will always lose out to English in situations like Rwanda, where there is a single national language and the main reason for learning a foreign language is communication with the rest of the world.
Vietnam, an ex-French colony, has long taught English as the main foreign language in its schools, and Madagascar, also formerly ruled by France, made English a national language last year.
English-speakers often assume that this world role for their language owes something to its huge vocabulary and wonderful literature, or at least to the fact that Hollywood speaks English. Nothing of the sort.
The sole reason is that the world's dominant power for the past two centuries has been English-speaking: Britain in the 19th century, and the United States in the 20th. Timing is everything, and English just happened to be the leading candidate when globalisation created the need for an agreed global second language.
* Gwynne Dyer's new book, Climate Wars, has just been published in New Zealand by Scribe.